Device for embedding a balloon, arranged on a catheter, in an implant and associated method

ABSTRACT

An embedding mould is configured for arrangement in the heating element. The embedding mould has a cylindrical cavity, which is dimensioned such that an assembly consisting of a catheter with balloon and an implant mounted on the outer side of the balloon can be arranged in the cavity of the embedding mould. A protective film is provided between an inner wall of the cavity of the embedding mould and the assembly.

PRIORITY CLAIM

This application is a 35 U.S.C. 371 US National Phase and claims priority under 35 U.S.C. § 119, 35 U.S.C. 365(b) and all applicable statutes and treaties from prior PCT Application PCT/EP2017/076962, which was filed Oct. 23, 2017, which application claimed priority from European Application EP 16196869.8, which was filed Nov. 2, 2016.

FIELD OF THE INVENTION

The invention relates to a device for embedding a balloon, arranged on a catheter, in an implant having a heating element, and to an associated method.

BACKGROUND

Within the context of the present invention, implants are to be understood to be endovascular prostheses or other endoprostheses, for example stents (vessel stents (vascular stents, including stents for use in the region of the heart and heart valve stents, for example mitral valve stents, pulmonary valve stents) and biliary duct stents), endoprostheses for closing persistent foramen ovale (PFO), stent grafts for the treatment of aneurysms, endoprostheses for closing an ASG (interatrial septum defect, atrial septal defect), and prostheses in the area of the hard and soft tissue. An implant of this type is often inserted via catheter into the organ or vessel to be treated.

Implants of this type in many cases have, at least in a portion, an open-work hollow-cylindrical (tubular) and/or hollow-conical structure, which is open at both longitudinal ends. The open-work structure is often composed of a plurality of struts, which are connected to one another and between which there are arranged continuous cutouts (gaps).

Such implants usually assume two states, specifically a compressed state with a small diameter and an expanded state with a larger diameter. In the compressed state, the implant can be introduced by the catheter into the vessel or organ to be treated, through narrow vessels, and can be positioned at the point to be treated. The implant is often mounted on a balloon of the catheter, i.e. on the outer side of the balloon, which balloon is also compressed. At the treatment site, the implant is then expanded by the balloon of the catheter so as to be transferred into the expanded state. The implant remains in the vessel or organ in the expanded state and is fixed there once the catheter has been removed from the body of the treated patient. As the implant is being transported through organs and vessels of the body to the treatment site in the compressed state, it is necessary that the implant sits firmly on the balloon and securely assumes the compressed state, so that the implant can be reliably guided to the treatment site, without damaging the vessels and organs through which it is passed. Furthermore, any damage to the filigree structure of the implant or the balloon or contamination of the implant or the balloon should be avoided. Contamination can occur in particular because many implants and/or balloons nowadays carry coatings which contain a therapeutically active material (medicament).

In order to arrange the implant on the balloon, the implant is fixed or mounted on the balloon, for example by crimping. However, the implant is only reliably held on the balloon by a process step referred to as embedding. In the case of embedding the balloon material is pressed or sunk into the gaps of the already-mounted implant. However, during this conventional embedding process, a strong inflation of the balloon or an expansion of the implant should be avoided.

Document US 2016/0096308 A1 discloses a heat exchanger, in which a pipe is arranged, for an embedding of this type of a stent in a balloon. The pipe serves to receive an assembly consisting of catheter with balloon and stent. This assembly is heated after arrangement thereof in the pipe in the heat exchanger, and the balloon is then pumped up via the catheter. The balloon is then held at a second temperature for a predefined period and is then cooled again

In a similar method known from document U.S. Pat. No. 6,063,092, an assembly consisting of a stent and a catheter arranged therein with balloon is arranged in a Teflon sleeve provided with a longitudinal slit. This sleeve is additionally placed in a casing of reducible diameter, which can be heated. Together with this casing, the sleeve and the assembly are arranged and heated in a heating block. An internal pressure is then applied to the balloon. After cooling and removal of the casing and sleeve, the stent is embedded in the balloon.

The above-described, known methods have the disadvantage that they require relatively long heating and cooling times and are complex on account of the necessary mounting of the sleeve over the assembly. In addition, there is a risk of cross-contamination in the case of implants with a medicament layer.

SUMMARY OF THE INVENTION

A preferred device of the invention provides a quick and thus economical embedding of an implant in a balloon. The preferred device can conduct an embedding method which avoids cross-contamination.

A preferred device has an embedding mould to be arranged in a heating element, which mould preferably has a high heat flux and a cylindrical cavity, preferably a tubular geometry with a continuous cavity, which is dimensioned in such a way (in particular in respect of length and diameter), that an assembly consisting of the catheter with the balloon to be embedded in the implant and with the implant mounted, preferably crimped, on the outer side of the balloon can be introduced into the cavity of the embedding mould and can be arranged in the cavity, wherein a protective film is provided between an inner wall of the cavity of the embedding mould and the assembly. In a preferred embodiment, the protective film moves with the assembly into the embedding mould for the embedding and the moves with the assembly out of the embedding mould after the embedding.

BRIEF DESCRIPTION OF THE DRAWINGS

Further objectives, features, advantages and possible applications of the invention will become clear from the following description of an exemplary embodiment of the device according to the invention and of the method according to the invention with reference to the drawings. Here, all features described and/or depicted in the drawings form the subject matter of the present invention, both individually and in any combination, also independently of their summary in the individual claims and the dependency references of the claims.

The drawings schematically show

FIG. 1 a device according to the invention in a perspective view from the side,

FIG. 2 the embedding mould with protective film of the device according to FIG. 1 in a perspective view from the side,

FIG. 3a a first step of an exemplary embodiment of a method according to the invention on the basis of a longitudinal section through the embedding mould and protective film,

FIG. 3b a second step of the method according to FIG. 3a with a longitudinal section through an assembly, and

FIG. 3c a third step of the method according to FIG. 3a with a longitudinal section through an assembly.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The protective film between an inner wall of the cavity of the embedding mould and the assembly in preferred devices facilitates the insertion and removal of the assembly into and from the cavity of the embedding mould. The low thickness, that is to say the thin wall, of a preferred protective film means that the heat insulation between heating element and assembly is minimal, so that the assembly is quickly heated and cooled. As a result, the process as a whole is thus accelerated and production costs are consequently saved. The protective film preferably has a thickness of less than 25 μm, particularly preferably of less than 20 μm. The thickness of the protective film is the smallest dimension of the measurements of the protective film.

In one exemplary embodiment of the present invention, the protective film is strip-like. The assembly can thus be particularly easily introduced into and removed from the embedding mould. Alternatively, the protective film can be formed as a layer arranged on the inner wall of the embedding mould. This is a particularly economical solution for the embedding mould.

The insertion and removal of the assembly and also the embedding are designed particularly simply and in an automatable manner if the cavity of the embedding mould runs parallel to the longitudinal direction of the embedding mould and is formed continuously, wherein the strip-like protective film bears loosely against the inner wall of the embedding mould, that is to say is not connected to the inner wall, and can be wound and/or unwound around the assembly and preferably protrudes beyond the continuous cavity of the embedding mould on both sides in the longitudinal direction of the cavity. The strip-like protective film can preferably be unwound from a roll, guided through the continuous cavity of the embedding mould, and wound onto a roll after use. A new portion of the protective film is used with each assembly in which the implant is to be embedded in the balloon, so that each portion of the protective film is used only once for the embedding. Contaminations and mechanical damage to the externally arranged elements of the assembly are thus avoided.

In order to ensure that the protective film securely surrounds the entire assembly, the width of the strip-like protective film in a preferred exemplary embodiment is greater than the circumference of the cavity of the embedding mould. It is thus ensured that the entire inner wall of the embedding mould is covered. The width of the protective film is measured perpendicularly to the longitudinal direction of the strip. By way of example, the width of the protective film is at least 105% of the circumference, preferably at least 110% of the circumference of the cavity of the embedding mould. Particularly good properties with regard to the insertion and removal of the assembly into/from the cavity of the embedding 2 s mould are ensured if the protective film consists of a plastic material, preferably at least one material of the group comprising fluoropolymers (for example polytetrafluoroethylene, perfluoroalkoxy polymers) and polyolefins (for example polyethylene, polypropylene).

It has already been explained above that it is advantageous if the embedding mould has a high heat flux. This requirement can be achieved primarily by a thin-walled geometry (low mass) and by a material having a high thermal conduction coefficient, preferably having a thermal conduction coefficient of more than 10 W/(m*K). On account of the high strength of metallic materials, metallic embedding moulds can be designed with particularly thin walls, and therefore a metallic material is preferred for the embedding mould. By way of example, a wall thickness of less than 0.2 mm is possible for aluminium alloys, or less than 0.1 mm for high-grade steel (for example 1.4310). In addition, metallic materials offer high thermal conduction coefficients of more than 10 W/(m*K), whereby quick heating and cooling times and therefore minimal process times are made possible. By way of example, high-grade steel (for example 1.4301, 1.4310), aluminium or aluminium alloy can be used as a material for the embedding mould.

For quick cooling and therefore a reduced process time, a cooling element is preferably arranged beneath the heating element, which cooling element has, on its upper side, at least one recess for the conduction of a cooling fluid (for example water or a gas, for example in the form of cooled nitrogen). The heating element can preferably be formed in two parts, wherein both parts are joined together to heat the assembly and to close the embedding 5 i mould. After the embedding, the two parts of the heating element can be opened again, so that the embedding mould with the assembly is accessible for the cooling fluid.

The above invention is also achieved by methods for embedding a balloon, arranged on a catheter, in an implant having an open-work structure, said method having the following steps:

-   -   producing an assembly consisting of a catheter with balloon and         the implant mounted on the outer side of the balloon, preferably         by crimping the implant onto the balloon, in particular onto a         middle portion of the balloon,     -   inserting the assembly into a cavity of an embedding mould,         which is lined on its inner wall with a protective film,     -   connecting the catheter to a fluid source,     -   heating the embedding mould with assembly in a heating element         for a predefined time,     -   applying a predefined first internal pressure to the balloon by         means of the fluid source connected to the catheter,     -   cooling the embedding mould with the assembly with a predefined         second internal pressure in the balloon, said pressure being         applied by means of the fluid source,     -   deflating (deaerating) the balloon after cooling the embedding         mould with the assembly,     -   removing the assembly from the embedding mould.

The preferred method according to the invention allows a quick and economical embedding of the implant in the balloon.

It is also advantageous if, prior to the introduction of the assembly into the cavity of the embedding mould, a strip-like protective film is wound around the assembly. The insertion of the assembly into the cavity of the embedding mould is facilitated as a result.

The removal is facilitated, and mechanical damage and cross-contamination are reduced if, when introducing the assembly into the embedding mould and/or removing the assembly from the embedding mould, the assembly is introduced into the cavity of the embedding mould and/or is removed from the cavity of the embedding mould together/jointly with the strip-like protective film. This means that the relative speed between assembly and protective film is zero in each case, that is to say that the assembly and protective film move at the same speed during introduction and/or removal. The protective film is more preferably unwound from the assembly following the removal.

As has already been described above, the embedding method is facilitated in that the strip-like protective film is unwound from a roll, is guided through the cavity of the embedding mould, and is wound up again onto a further roll, preferably after use for a single assembly.

The device according to the invention shown in FIG. 1 for embedding a balloon 30 of a catheter 29 in an open-work implant, for example a stent 31, has a two-part heating element 3, in which a hollow-cylindrical embedding mould 5 is arranged. For this purpose, corresponding cavities 7 are provided in each part of the heating element 3. The heating element 3 is designed so that it can transfer heat to the embedding mould 5, for example by means of radiation, convection, or contact. For this purpose, the heating element 3 can be designed for example as a resistance heater, induction heating element, capacitive heating element, or as a heating element that works with infrared radiation.

In order to embed a balloon 30, arranged in a catheter 29, in an implant in the form of a stent 31 which has an open-work structure (gaps) at least in portions, an assembly consisting of the stent 31 mounted on the balloon 30 and of the balloon 30 with catheter 29 (see FIGS. 3b and 3c ) is introduced into the continuous cavity 9 of the embedding mould 5. In order to achieve a good transfer of heat from the heating element 3 to the embedding mould 5, the mould consists of a thin-walled geometry (see above) and a material having a high thermal conduction coefficient, for example a metallic material (for example high-grade steel, an aluminium alloy, or aluminium), or very thin-walled glass.

As shown in FIG. 3a , a strip-like protective film 11 is guided through the embedding mould 5 and for example can be unwound from a roll (not depicted) and can be wound up again onto a roll (not depicted) once it has been passed through the embedding mould 5. The protective film 11 is laid within the continuous cavity 9 of the embedding mould 5 by a twisting movement (see arrow 13 in FIG. 2 and detail A in FIG. 1) in such a way that the protective film 11 (as considered in cross-section) forms an overlapping “O” so to speak, which bears internally against the inner wall of the continuous cavity 9 of the embedding mould 5 and externally against the assembly. For this purpose, the protective film 11, which preferably consists of a PTFE material, has a width B that is greater than the circumference of the embedding mould 5 along the inner wall thereof.

The assembly, as illustrated in FIG. 3b , is preferably inserted into the inner volume of the protective film 11, formed by the laying of the protective film 11 against the inner wall of the cavity, before an end 22 of the embedding mould 5 and is then introduced into the embedding mould 5 together with the protective film 11 by drawing the protective film 11 through the cavity 9 of the embedding mould 5. The direction of the joint movement of assembly and protective film 11 is denoted in FIG. 3b by the arrow 35. The assembly consisting of the catheter 29 with balloon 30 and the implant mounted on the outer side of the balloon, for example a stent 31, was manufactured beforehand by crimping the stent 31 onto a middle region of the balloon 30.

By lining the continuous cavity 9 with the protective film 11, neither the balloon 30 nor the stent 31 comes into contact with the material of the embedding mould 5, and therefore there is no mechanical abrasion created there, that is to say no frictional and/or shear forces between assembly and embedding mould 5. Once the assembly has been fully introduced into the continuous cavity 9 of the embedding mould 5 (position as shown in FIG. 3c ), each part of the two-part heating element 3 is moved towards the embedding mould 5 and encloses this preferably completely. At the same time, the catheter 29 is connected to a fluid source. The assembly arranged in the embedding mould 5 is now heated by means of the heating element 3 to a predefined temperature, which usually lies above the glass transition point of the balloon material (approximately 55° C. to 150° C.). The internal pressure in the balloon 30 is then increased (approximately 5 to 30 bar) by means of the fluid source connected to the catheter 29, so that the balloon expands slightly. The balloon material is thereby pressed into the gaps of the stent 31 and thus embedded in the stent 31. With continuously applied internal pressure, both parts of the heating element 3 are then removed again from the embedding mould 5, and the embedding mould 5 can cool down. The cooling process can be assisted by a cooling element 25 arranged beneath the embedding mould 5 or the heating element 3, with a cooling fluid, for example air, being conducted to the embedding mould 5 through the pipe of the cooling element and openings 26 arranged on the upper side. A quicker cooling of the embedding mould 5 with the assembly can be achieved as a result.

After sufficient cooling, that is to say usually beneath the glass transition point of the balloon material (for example beneath 55° C.), the pressure in the catheter 29 is reduced again to ambient pressure by the fluid source, and the assembly together with the protective film 11 is removed from the embedding mould 5. The direction of the joint movement of protective film 11 and assembly is depicted in FIG. 3b by the arrow 36. A new portion of the protective film 11 is then automatically placed in the embedding mould 5 for the next embedding process. For this purpose, the protective film can be moved further (what is known as an empty run) for example by being drawn through the embedding mould 5 in the direction of the arrow 36 (see FIG. 3b ). Cross-contamination, for example by medicaments applied to the surface of the stent, is avoided as a result.

Outside the embedding mould 5, the strip-like protective film 11 can be easily tom off, so that the assembly with the balloon 30 embedded in the stent 31 can be easily removed. Mechanical abrasion (that is to say frictional and/or shear loads) at the assembly, in particular at the stent 31, is avoided as a result.

As has already been explained above, the protective film 11 is moved further through the continuous cavity 9 of the embedding mould 5 for the next embedding process, so that a new portion of the protective film 11 is used for the next embedding process. The used protective film is, for example, wound up again on a roll after having been guided through the cavity 9 of the embedding mould 5.

The protective film 11 can consist for example of a plastic material, such as PTFE, PFA, PE, PP, PA, etc. In particular, fluoropolymers have suitable properties with regard to temperature resistance and coefficient of friction.

The above-described device according to the invention and the method according to the invention allow a quick and economical embedding of a stent 31 in a balloon 30.

LIST OF REFERENCE SIGNS

-   3 heating element -   5 embedding mould -   7 cavity -   9 cavity -   11 protective film -   13 arrow -   21 first end of the embedding mould 5 -   22 second end of the embedding mould 5 -   25 cooling element -   26 opening -   30 balloon -   31 stent -   29 catheter -   35 arrow -   36 arrow -   A detail from FIG. 1 -   B width of the protective film 11 

1. A device for embedding a balloon arranged on a catheter in an implant having an open-work structure, said device comprising: a heating element; an embedding mould configured to be arranged in the heating element, wherein the embedding mould has a cylindrical cavity dimensioned in such a way that an assembly consisting of the catheter with balloon and the implant mounted on the outer side of the balloon can be arranged in the cavity of the embedding mould; and a protective film configured to be movable with the assembly into a position between an inner wall of the cavity of the embedding mould and the assembly for the embedding.
 2. The device according to claim 1, wherein the protective film is strip-like or is formed as a layer arranged on the inner wall of the embedding mould.
 3. The device according to claim 2, wherein the cavity (9) of the embedding mould runs parallel to the longitudinal direction of the embedding mould and is formed continuously, wherein the strip-like protective film bears loosely against the inner wall of the embedding mould and can be wound and/or unwound around the assembly and protrudes beyond the continuous cavity of the embedding mould on one or both sides in the longitudinal direction of the cavity.
 4. The device according to either one of claim 2, wherein the width of the strip-like protective film is greater than the circumference of the cavity of the embedding mould.
 5. The device according to claim 1, wherein the protective film consists of a plastic material.
 6. The device according to claim 1, wherein the embedding mould has a high heat flux.
 7. The device according to claim 1, further comprising a cooling element arranged beneath the heating element, which cooling element has at least one opening on its upper side for the conduction of a cooling fluid.
 8. A method for embedding a balloon, arranged on a catheter, in an implant having an open-work structure, said method comprising the following steps: producing an assembly consisting of a catheter with balloon and the implant mounted on the outer side of the balloon, inserting the assembly into a cavity of an embedding mould, which is lined on its inner wall with a protective film, connecting the catheter to a fluid source, heating the embedding mould with assembly in a heating element for a predefined time, applying a predefined first internal pressure to the balloon by the fluid source connected to the catheter, cooling the embedding mould with the assembly with a predefined second internal pressure in the balloon, deflating the balloon after cooling the embedding mould with the assembly, removing the assembly and protective film from the embedding mould.
 9. The method according to claim 8, wherein the protective film is a strip-like protective film and, prior to the introduction of the assembly into the cavity of the embedding mould, the strip-like protective film is wound around the assembly.
 10. The method according to claim 9, wherein the assembly is introduced into the cavity of the embedding mould and is removed from the cavity of the embedding mould together with the strip-like protective film, and the protective film is unwound from the assembly following the removal of the assembly.
 11. The method according to claim 8, wherein the strip-like protective film is unwound from a roll and is guided through the cavity of the embedding mould with the assembly.
 12. The device of claim 5, wherein the plastic material is selected from the group consisting of PTFE, PFA, PE and LDPE.
 13. The device of claim 1, wherein the protective film is movable with the assembly out of the mould after the embedding.
 14. A device for embedding a balloon arranged on a catheter in an implant having an open-work structure, said device comprising: a heating element; an embedding mould configured to be arranged in the heating element, wherein the embedding mould has a cylindrical cavity dimensioned in such a way that an assembly consisting of the catheter with balloon and the implant mounted on the outer side of the balloon can be arranged in the cavity of the embedding mould; and a protective film between an inner wall of the cavity of the embedding mould and the assembly
 15. The device according to claim 14, wherein the protective film is connected to an inner wall of the embedding mould. 